All measured data does, in principle, contain errors and in many cases the measured data is, additionally, not continuously available. In addition to being dependent on the inherent characteristics of the sensors, the measured data is, furthermore, frequently dependent on environmental conditions. Sensor errors or measurement errors can be subdivided into quasi-stationary components which are constant over a plurality of measurements, e.g. a so-called offset, and statistical components which are random from measurement to measurement, e.g. noise. Whereas the random components cannot in principle be deterministically corrected, quasi-stationary errors can generally be corrected provided that they are observable. Non-correctable, significant errors can normally be at least avoided provided that they are recognizable.
In connection with this, different sensor fusion methods, which are normally also suitable for correcting or filtering measured data from different sensors or sensor systems, are already known in the prior art. Particularly in the automotive sector, special requirements must be taken into account since a plurality of different sensors capture a common environmental situation or a motor vehicle state by means of different measuring principles and describe this environmental situation or this motor vehicle state by means of a plurality of different measured data. The greatest possible resilience to random interference and a recognition and compensation of systematic errors are thus required for a sensor fusion, which can be used in the automotive sector. Similarly, temporal influences on the measured data must be corrected and temporary outages or the unavailability of sensors must be bridged.
DE 10 2012 216 211 A1 describes a method for selecting a satellite, wherein the satellite is a satellite of a global navigation system. Before such a satellite is used to determine the position of a vehicle, the plausibility of the GNSS signals received is verified in different ways. Different redundancies or known relationships are used, in each case, for this verification. Thus, DE 10 2012 216 211 A1 discloses, for instance, determining both the distance between the vehicle and the satellite and the relative speed of the vehicle to the satellite from the signal of a satellite. The distance can, in this case, be determined by means of the transit delay of the signal, while the relative speed can be determined by means of a phase measurement of the signal. Since the distance and the relative speed are interdependent, they can be verified against one another.
Furthermore, the values determined from the signal can be verified against known boundary conditions, since a vehicle usually travels within a particular speed framework. The document also describes how, on receiving multiple signals from different satellites, the distances from multiple satellites are determined and these distances are simultaneously verified with respect to one another by means of trigonometric relationships and the known distance of the satellites. Finally, it is also possible to verify the distance determined from the signal or the speed determined from the signal by means of other sensors, which also allow a determination of the position or speed. If the signals of a satellite cannot be verified, this satellite is not used for determining the position or for determining the speed.
A sensor system comprising a plurality of sensor elements is known from DE 10 2010 063 984 A1. The sensor elements are designed so that they at least partially capture different primary measured quantities and at least partially use different measuring principles. Other measured quantities are then at least partially derived from the primary measured quantity of the sensor elements. Furthermore, the sensor system comprises a signal processing device, an interface device and a plurality of functional devices. The sensor elements and all of the functional devices are connected to the signal processing device. The primary measured quantities therefore provide redundant information which can be compared with one another in the signal processing device or which can support one another. From the comparison of the observables calculated in different ways conclusions can be drawn regarding the reliability and accuracy of the observables. The signal processing device qualifies the accuracy of the observables and provides the observables, together with an indication of the accuracy, via an interface device to various functional devices.
DE 10 2012 219 478 A1 discloses a sensor system for independently evaluating the accuracy of the data of the sensor system. The sensor system is preferably used in motor vehicles and has a plurality of sensor elements which are designed such that they capture at least to some extent different primary measured quantities or use at least to some extent different measurement principles. Furthermore, the sensor system comprises a signal processing device which evaluates the sensor signals at least to some extent collectively and, at the same time, evaluates the information quality of the sensor signals. The signal processing device additionally provides a piece of information about the accuracy of at least one datum of a physical variable, wherein the datum of the physical variable is calculated on the basis of the sensor signals from sensor elements which either directly capture the physical variable, or the physical variable can be calculated from the sensor signals thereof. The piece of information about the accuracy of the datum is then calculated on the basis of sensor information which is available in a redundant manner, directly or indirectly.
However, the generic methods and sensor systems known from the prior art are disadvantageous inasmuch as they do not take account of the availability of the correction measurements depending on the surroundings or situation. Even the total failure of certain systems is frequently ignored. This leads to non-optimum results of the fused and corrected data.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.